There are several constraints on the video bit rate of a sequence coded on a DVD, e.g., device processing capacity, read rate, and seek time. The problem has been how to meet these constraints, yet provide acceptable video quality and DVD performance.
One approach has been to apply a rate control algorithm based on MPEG-2 TM5 to video sequences. However, this algorithm does not handle frame complexity changes due to scene changes very well, failing to allocate bits proportionately and timely with the scene changes. A two-pass version of this algorithm has been implemented to react more rapidly to the scene changes. However, there is an initial learning period after each scene change in which the algorithm must determine the appropriate bit allocation. Moreover, the rate control algorithm does not adequately model decoder buffer conditions, such that the determined bit rate may result in buffer underflow.
Accordingly, there is a need in the art for an efficient way to control the video bit rate within the above-mentioned constraints and provide acceptable video quality and DVD performance.